CPOS Seminar: "Improving the efficiency of aqueous tin batteries using low-cost electrolyte additives"
Speaker: Emma J. Latchem, Postdoctoral Researcher, Clément Group, Department of Materials, UCSB
There is an urgent need for long-duration electrical energy storage (EES), so that intermittent renewable energy sources can be fully utilised on the electricity grid.1 Leading EES devices, such as the lithium-ion battery, are currently too expensive to deploy on a large scale. This has motivated efforts to develop new low-cost technologies, such as rechargeable aqueous zinc batteries.2 However, zinc batteries suffer from parasitic side reactions, such as the hydrogen evolution reaction (HER), and the formation of dendrites and dead zinc.3,4 Though tin is more expensive than zinc, it is less prone to HER and dendrite formation. Tin aqueous batteries have the potential to outperform their zinc counterparts as more of the active material can be utilised more efficiently.4,5 Specifically, a reversible 4-electron tin battery has recently been demonstrated at room temperature.5 This battery has double the theoretical capacity of standard tin batteries, which are typically limited to 2-electron redox. This was achieved using lean-electrolyte conditions and an ion-selective membrane to facilitate the second 2-electron oxidation on discharge. Nevertheless, the second 2-electron oxidation of Sn(II) to Sn(IV) is kinetically hindered, making Sn(II) prone to chemical oxidation and self-discharge at the opposite electrode.
In this work, we use a new cell design to successfully replicate 4-electron tin electrochemistry at room temperature and investigate the impact of low-cost additives on the kinetics and thermodynamics of the redox processes. With nuclear magnetic resonance (NMR) spectroscopy, we track how tin-additive interactions can be tuned to increase battery efficiency and reversibility. Our preliminary results indicate that additives that interact with tin ions, but do not strongly coordinate with them, are most favourable. Additionally, additives containing oxidisable hydroxyl groups are found to degrade in the battery environment and are therefore best avoided. Future work will focus on investigating whether these additives can also enhance the percentage utilisation of material within the battery.
References:
(1) Dunn, B.; Kamath, H.; Tarascon, J.-M. Electrical Energy Storage for the Grid: A Battery of Choices. Science 2011, 334 (6058), 928–935. https://doi.org/10.1126/science.1212741.
(2) Ahn, H.; Kim, D.; Lee, M.; Nam, K. W. Challenges and Possibilities for Aqueous Battery Systems. Commun Mater 2023, 4 (1), 1–19. https://doi.org/10.1038/s43246-023-00367-2.
(3) Kumari, P.; Kundu, R. Zinc-Ion Batteries: Promise and Challenges for Exploring the Post-Lithium Battery Materials. ACS Appl. Energy Mater. 2024, 7 (21), 9634–9669. https://doi.org/10.1021/acsaem.4c02016.
(4) Lan, X.; Zhang, Z.; Liao, G.; Du, W.; Zhang, Y.; Ye, M.; Wen, Z.; Tang, Y.; Liu, X.; Li, C. C. Recent Advances in Metallic Tin Anodes: An Emerging Field of Rechargeable Aqueous Batteries. ACS Appl. Mater. Interfaces 2025, 17 (17), 24763–24777. https://doi.org/10.1021/acsami.5c01275.
(5) Wang, J.; Catalina, S. K.; Jiang, Z.; Xu, X.; Zhou, Q. T.; Chueh, W. C.; Mefford, J. T. A Reversible Four-Electron Sn Metal Aqueous Battery. Joule 2024, 8 (12), 3386–3396. https://doi.org/10.1016/j.joule.2024.09.002.
